1. Field of the Invention
The invention relates generally to sterilization devices and more particularly to a hand-held ultraviolet radiation sterilization device and a method of using the same.
2. Background
UV radiation is a form of electromagnetic radiation that contains measurable wavelengths in the 4-400 nanometer range. Ultraviolet (UV) radiation is a well-known sterilization agent. The use of UV light for germicidal, bactericidal and pathogenicidal effects is well known. Suitable wavelengths for this effect is 300-200 nanometers.
Ultraviolet light is effective at eradicating germs, bacteria, viruses and other pathogens. Ultraviolet light has been used in a number of applications, including low level uses in dermatology, tanning, dental procedures, and small-scale sterilization of objects or instruments. However, to date large scale usage of ultraviolet light in hospitals or other large areas has been limited, principally because exposure to ultraviolet light at an intensity necessary for effective and efficient eradication or sterilization of pathogenic agents is very harmful to the human body. Specifically, the ultraviolet radiation required to effectively and efficiently eradicate pathogenic agents should be an intensity ranging from 2000-6000 microwatts/cm.sup.2. Human contact with ultraviolet light in this range requires protective clothing, including covering the skin and eyes. UV light has been used in operating rooms, wards, and nurseries of hospitals, generally by being fixed to the walls or ceilings. The danger to humans posed by ultraviolet radiation requires these UV light sources to be shielded to prevent direct or reflected UV light from striking humans. The stationary and shielded light fixture is therefore only partially effective eradicating pathogens or of micro-organisms because there are many surfaces and hidden areas that can escape direct contact by the UV radiation.
In order for UV radiation to eradicate or kill micro-organisms, it is generally believed that the UV rays must directly strike the micro-organisms. The exposure to UV light necessary to kill bacteria (or the "kill" factor) is a product of time and intensity.
U.S. Pat. No. 2,215,635 issued to Collins (Sep. 24, 1940) discloses an adjustable ultraviolet light fixture apparatus for hospital operating rooms for treating bacteria. Collins describes maintaining the intensity of the radiation "at the highest value to which the uncovered viscera of a patient may be exposed without harmful adhesions or other undesired results ensuing." Col. 1, lines 35-38. The device includes a conventional light source and an ultraviolet radiation source attached to a positional support arm, the device fixedly mounted above an operating table to direct the light and UV radiation at the patient. The UV radiation was believed to possess bactericidal and therapeutic effects.
U.S. Pat. No. 4,952,369 issued to Belilos (Aug. 28, 1990) describes a portable, pocket-size, ultraviolet flashlight that can be used by ordinary individuals to kill germs and viruses on objects like toilet seats, flatware, and telephones. The flashlight includes a housing, an ultraviolet light source, an on/off switch, and a gravity switch that limits the activation of the ultraviolet light source to the position wherein the light source is facing downward. By limiting the activation of the UV source to when the device faces downward the device sought to reduce harm to eyes. The UV lamp utilized by Belilos can be any type of light source generating UV light in sufficient intensity to disinfect objects at relatively short distances. Col. 2, lines 6-9.
U.S. Pat. Nos. 4,786,812, 5,029,252, and 5,446,289 describe devices for sterilizing air and instruments by passing the air or instruments through the sterilization devices. U.S. Pat. No. 4,786,812 issued to Humphreys (Nov. 22, 1988) describes a device with a fan and ultraviolet light source in a housing whereby the fan draws unsterilized air into the housing and the air is sterilized and then return to its environment. U.S. Pat. No. 5,029,252 issued to Ameseder (Jul. 2, 1991) describes an apparatus with a housing containing an ultraviolet light source and the housing has openings for instrumental devices, like toothbrushes. The instrumental device is placed in the housing and sterilized by the ultraviolet light. U.S. Pat. No. 5,466,289 issued to Shodeen et al. (Aug. 29, 1995) describes a pass-through sterilization chamber where items are placed in the sterilization chamber and subjected to ultraviolet radiation.
There is a need for a UV sterilization device with sufficient intensity to kill germs, bacteria, viruses, and other pathogens and microorganisms efficiently in a large area like a hospital room. There is also a need for a hand-held device that supplies sufficient intensity to a surface or object to destroy most pathogens or microorganisms. There is further a need for a device that is capable of sterilizing rooms like, hospital operating rooms, wherein the device can reach all corners or all surfaces of the room.